1. Field of the Invention
This invention relates to vacuum breaker valves used in fluid treatment or processing facilities. More particularly, it is concerned with a simple and reliable vacuum breaker valve which is designed for cleaning in place, avoiding the need for removal and disassembly during the cleaning process.
2. Description of the Prior Art
The use of vacuum breaker valves in liquid processing plants is well known in the art. Such valves are sometimes also known as "anti-siphon" valves, which serve to inhibit the creation of a vacuum when pressure in a fluid conduit changes to cause a reversal of the flow of treated liquid. Vacuum breaker valves are often required in systems handling or treating potable water, pasteurized milk or other flowing liquid food products in order to prevent the flow of contaminated or untreated liquid into a storage container or supply line.
Vacuum breaker valves are often positioned in elevated locations which makes access for cleaning difficult. For example, a vacuum breaker valve may be located on an elevated conduit which is several meters above the plant floor and cannot be reached without ladders, cranes or the like. While many dairies or food treatment plants use clean in place (CIP) systems to maintain sanitation and cleanliness of the system, vacuum breaker valves have typically not been designed with this capability. As a result, cleaning personnel routinely overlook the need to maintain and clean the vacuum breaker valve until they clog, fail, or become severely contaminated.
U.S. Pat. No. 4,339,111 to Welch entitled Clean In Place Diaphragm Valve discloses a valve useful in the sanitary food industry having clean in place capabilities. However, the valve disclosed therein is designed for sampling purposes to obtain a selected sample of the liquid, and is not capable of performing vacuum breaker functions. Furthermore, its operating member is a diaphragm, which is subject to fatigue and failure.
Other vacuum breaker valves are shown in U.S. Pat. Nos. 2,686,528, 3,145,724, 4,712,574, and 4,998,554. However, none of these vacuum breaker valves are capable of CIP operation.
Thus, there has developed a real need for a simple, reliable, and economical vacuum breaker valve which is capable of clean in place operation.